(1) Field of the Invention
The present invention relates to a missile ejection system and more particularly to an ejection system using steam as a prime mover or dynamic force to eject a missile.
(2) Description of the Prior Art
Current naval missile ejection systems are totally reliant on ordnance gas generators. Ordnance gas generators produce a hot exhaust gas via a controlled propellant burn that provides the dynamic force used to eject the missile from a missile launch tube or capsule.
The ordnance gas generator was preceded in early launching systems by a high pressure air systems. The high pressure air systems were large and complex due to requirements for air flasks, piping and associated isolation valves. The move to gas generators was necessitated by a need to reduce system complexity, reduce maintenance and increased launching system operational confidence.
However, ordnance gas generators have brought the added burden of explosive ordnance safety concerns. These safety concerns include significant costs for safe transport; bunkering and test firings to ensure explosive grain stability and safe ejection performance. Additional costs for aging/performance of the grain using analysis and live fire tests are expensive.
Also, when gas generators reach the expected acceptable performance end of life, the generators must be disposed at a typically high cost due to explosive and hazardous material. Overall, the cost in labor, analysis, documentation and logistical storage and transport needed to support current gas generator technology is significant.
As such, a need exists to remove hazardous material disposal costs for post missile launches and costs associated with outdated or exceeding operational service life disposal of gas generators.
A further need exists to eliminate explosive ordnance bunker maintenance and personnel monitoring costs.
As discussed below, alternative methods for submerged missile ejection are the current use of gas generators or a return to the use of high pressure air for an ejection pulse.
Paterro (U.S. Pat. No. 6,290,184) describes two steam generators combined with air compressors that supposedly produce a constant flow of steam and air for propulsion. However, the cited reference does not describe a static pressure vessel that contains water at high temperature and pressure until a firing valve allows an explosive release of pressure, thus flashing the water to steam and providing thrust for missile ejection.
Barakauskas (U.S. Pat. No. 3,182,554) discloses a solid fuel gas generator for the missile ejection system. The cited reference discloses that the water contained in a cooling chamber has a primary use of cooling a high temperature ejection gas from a gas generator. The high temperature ejection gas needs to be cooled to prevent damage to the missile structure and rocket motor. Therefore, the water in this case is primarily used for hot ejection gas cooling with some residual thrust provided when the cooling water flashes to steam. The cited reference does not use water heated to steam and pressurized in a pressure vessel to provide the sole means of eject thrust for a missile or other payload from a launch tube.
Pauletich (U.S. Pat. No. 3,944,019) is designed as a constant source of steam suspended from a cable at sea. The steam would be pulsed into a bell chamber to produce a sound pulse supposedly useful for geological study of the ocean floor. The cited reference does not have a static pressure vessel filled with water that would be maintained when armed to eject a missile at high temperature and pressure until a firing valve allows an explosive release of pressure.
Nissley, Jr. (U.S. Pat. No. 4,014,246) uses a boiler to provide a steam source to a pressurized volume referred to as a “rocket” for launching a flying vehicle from a ground rail launch system. In the cited reference, the steam producing boiler is separate from the pressurized volume (rocket) and is connected via a piping header from the boiler to the pressurized volume. The cited reference is not structurally designed as a single unit that incorporates a pressure vessel, water supply system, electrical energy resistance heater to heat the water and firing valve in a common unit.
Johnson (U.S. Pat. No. 4,724,738) describes a design that does not utilize a pressure vessel to contain a heated pressurized water source. The water used in the cited reference is contained in the “Rocket” launch cylinder and functions primarily as a cooling source to lower the temperature of the rocket booster motor when initiated. The cited reference does not utilize a pressure vessel to contain a heated pressurized water volume until the firing valve releases the pressurized water that flashes to steam and ejections the missile or payload from the launch tube.
Lenz (U.S. Pat. No. 4,767,364) describes a ship propulsion source using a steam boiler and piped steam sourcing two propulsion jets fixed to the aft end of a ship. This cited reference does not utilize a static pressure vessel to contain a heated and pressurized water source designed for explosive release of steam to launch a missile or payload for a missile launch tube.
Turner et al. (U.S. Pat. No. 5,737,962) utilizes a steam source from a boiler that is piped to a torpedo test stand. The piped steam source is connected to a torpedo propulsion afterbody and thus provides the energy required to operate the propulsion motor at rated speed and power, without using toxic fuel that is typically used for torpedo propulsion. However, the cited reference is not designed as a unitary pressure vessel missile steam ejection launching source.